Commuter train services on the Melling line will return to normal this morning after the removal of the crashed Matangi unit from the tracks.

KiwiRail would not say whether all its Matangi trains had been inspected after Tuesday's crash, in which the Melling train crashed into a concrete buffer at the end of the track. It was the second time a Matangi had hit a barrier in the same spot.

The latest crash thrust the front carriage two metres in the air, after its driver told passengers: "I've got no brakes, brace yourselves." Two people were taken to hospital.

KiwiRail spokesman David Miller confirmed its Matangi trains were running yesterday. "KiwiRail takes every possible step to ensure the reliability of our trains and the safety of passengers and staff.

"All of the Matangi and Ganz Mavag trains undergo regular maintenance checks and we conduct ongoing safety briefings, monitoring, and training for our drivers and staff.

"A thorough investigation into [Tuesday's] incident is under way and it is too early to speculate on any possible cause. However, we reassure customers that their safety is paramount at all times."

In June last year, a problem was found with the coupling pin in eight Matangi units. In a worst- case scenario, it could have seen a passenger fall between two moving carriages.

In April this year Matangi trains were pulled from service for a weekend because of an "earthing problem".

In April last year, in the same spot as Tuesday's crash, a Matangi train crashed into the safety barrier, leaving some passengers with minor injuries.

A Traffic Accident Investigation Commission (TAIC) investigation into that crash continues. KiwiRail has completed its own investigation but would not reveal details other than to say no fault was found with the track or train.

TAIC spokesman Peter Northcote said the 13-month wait for its report into the April 2013 incident was normal, but if any problems had been uncovered during the investigation that needed urgent action KiwiRail would have been informed.

There was no reason KiwiRail could not release its own findings into the accident earlier, he said. "The world doesn't have to hold its breath for us."

Greater Wellington Regional Council, which owns the train fleet, said yesterday: "If KiwiRail or TAIC had concerns about the safety of the Matangi fleet, we would have expected to be informed immediately."